通过mongoose为mongodb中集合的文档中的每个嵌套对象创建Id

const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/mydatabase', { useNewUrlParser: true, useUnifiedTopology: true });

const subSchema = new mongoose.Schema({
    // 定义嵌套对象的属性
    name: String
});

const mainSchema = new mongoose.Schema({
    // 定义文档的其他属性
    nestedObject: subSchema
});

const MainModel = mongoose.model('Main', mainSchema);

const main = new MainModel({
    nestedObject: {
        _id: new mongoose.Types.ObjectId(),
        name: 'Nested Object'
    }
});

main.save((err, result) => {
    if (err) {
        console.error(err);
    } else {
        console.log(result);
    }
});